!7

p {
  CircularFifoBuffer<Character> b = new CircularFifoBuffer<Character>(4);
  b.add('k'); b.add('i'); b.add('l'); b.add('l'); b.add('l');
  S s = getLast(b, 4);
  assertEqualsVerbose("illl", s);
  assertEqualsVerbose(1L, b.getBase());
}

static S getLast(CircularFifoBuffer<Character> b, int n) {
  n = Math.min(n, b.size());
  new StringBuilder buf;
  Iterator<Character> it = b.getBackingStore().descendingIterator();
  for (int i = 0; i < n; i++)
    buf.append(it.next());
  return buf.reverse().toString();
}